The present invention relates to integrated circuits, and more particularly to heat exchanger systems for integrated circuits.
After a short period of use, the internal components of electronic devices such as computers become heated. As a result, system performance suffers and system reliability degrades. However, performance and reliability may be restored by cooling the electrical components to remove excess heat.
In general, heat may be transferred from one body to another simply by bringing a cool body into contact with a warm body because heat tends to flow from warmer areas to cooler areas. However, simply touching two bodies together rarely yields an efficient heat transfer because pockets of heat insulating air are often trapped between irregularities in the mating surfaces. The efficiency of a heat transfer between two bodies may be improved using a thermal interface material (TIM). Typically, TIM""s are malleable materials that conduct heat well, such as metallic or polymeric materials, thermal greases, thermal gels, or thermal greases/gels filled with metallic particles.
In computer systems, a computer chip may be cooled by coupling it with a heat exchanger. Because of space and other constraints, it is often impractical to mate the chip and heat exchanger directly. Typically, the chip is bonded to a heat conductive metal block using a TIM. The metal block is then coupled with a remote heat sink via a heat pipe. In most cases, the heat pipe is soldered at one end to the metal block and at the other to the heat sink.
Heat pipes are known for having a small cross-sectional area and a low resistance to the transfer of thermal energy. Components of a heat pipe typically include a vacuum-sealed heat conductive tube containing a liquid and a porous metal wick. Often, the wick is which may be attached to an inner surface of the heat conductive tube. As the liquid inside the heat pipe vaporizes at the pipe""s hot end and condenses at the pipe""s cool end, heat is transferred from the metal block to the heat sink. Once condensed, the liquid flows via capillary action of the wick back to the hot end, and the circulation cycle continues as long as the metal block supplies heat and the temperature of the heat sink is low enough. Vacuum pressure inside the heat pipe ensures an efficient circulation cycle because liquids vaporize quickly at low pressures.
Generally speaking, heat is transferred more efficiently in desktop computer systems than in mobile computer systems. In desktop systems, the chip manufacturers bond the metal block to the chip using a high quality TIM. Whereas in mobile systems, original equipment manufacturers (OEM""s) bond the block to the chip using a low quality TIM and an aggressive attachment method that challenges the reliability of the chip. Consequently, mobile platform heat exchangers tend to operate less efficiently than their desktop platform counterparts.
Thus, a solution is needed that increases the effectiveness of mobile platform heat exchanger systems.